Endocrine System Flashcards
What are the 4 ways Cells communicates?
Contact-dependent
Paracrine
Synaptic
Endocrine
What does the Endocrine system do?
Discrete glands and tissues (chemical messengers), that enter the bloodstream (dispersed through body) exert on specific Target cells with high affinity receptors
What is the Main function of Endocrine Cells?
Secrete Hormones
What are the Organs/Glands form together by endocrine cells?
Adrenal, Pituitary, Pineal
What are the Specialised Organs formed from discreet clusters of Endocrine cells?
Ovary, Testis, Pancreas
Where are Endocrine cells dispersed?
Diffuse in Enteroendocrine system in gut
What is the Function of the Pituitary gland?
Secrete large number of hormones
What are the Active Peripher endocrine cells in the Pituitary gland?
Adrenal, Thyroid, Testis, Ovary
Describe what the Pituitary gland looks like?
Bean shaped under brain linked by pituitary stalk, devided anatomically anterior and posteriorly
What are the 3 distinct components of epithelial tissue in the Anterior Pituitary?
Pars Distalis - major portion
Parts Tuberalis - layer of cell running up stalk
Pars Intermedia - narrow band bordering p lobe
What are the 3 Cell types (staining pattern) of the Anterior Pituitary?
Acidophilis (acidic dyes)
Basophilis (basic dyes)
Chromophobes (no cytoplasmic staining)
What are the 2 types of Acidophilis cells in the A. Pituitary?
Somatotrophs - growth Hormone
Lactotrophs - prolactin
Describe Somatotroph cells?
Stimulates cell growth and replication , increasing rate of protein sysnthesis and growth hormone (acromegaly)
Describe Lactotroph cells?
Stimulates mammary gland development - in pregnancy stimulates milk production and increases in size
What are the 4 Types of Basophilis Cells?
Corticotrophs - ACTH
Gonadotrophs - FSH & LH
Thyrotrophs - (TSH)
Chromophores
Describe the Corticotroph cells?
Release steroid hormones from adrenal cortex (cortisol)
Describe Gonadotrophs cells?
Regulate activity of gonads (ovary & testis)
FSH - follicle development and secretion
LH - induces ovulation
Describe Thyrotrophs cells?
Stimulate growth thyroid epithelial cells, release thyroid hormones
Describe chromophores?
Fail to stain, too few granules, 5 types
Describe the Posterior Pituitary?
Contains Neural lobe - continuation of hypothalamic region of brain with axons of hypothalamic neurons
What are the 2 Hormones of the Posterior Pituitary?
ADH - decrease h2o loss by kidneys
Oxytocin -Promotes contraction of smooth muscle, myoepithelial cells breast
Where is the Pineal Gland?
Located under Brain , composed of lobules
What are the 2 types of Cells in the Pineal gland?
Pinealocytes - neuron-like cells produce melatonin
Glial cells - bipolar cells runs between nests of pinealocytes
What is Melatonin responsible for?
Secreted by pineal gland, responds to light and regulates body- declines with agin and trigger changes in system
Describe the Thyroid gland?
Bilobed, Curves across anterior surface of trache, lobes connected by isthmus
What are the 3 Thyroid hormones?
Thyroxine - T4
Triiodothyronine - T3
Calcitonin (calcium homeostatis)
Describe Thryoid Cells?
Hollow spheres of cuboidal epithelial cells, lumen filled with colloid, surrounded by basement membrane enclose c cells
What are the 2 Thyroid states?
Under active - increase colloid flat
Overactive - decrease colloid - tall cells
Describe Parathyroid glands?
In posterior surface of thyroid, seperated by dense capsular fibres of thyroid, contains PTH hormone
What are the 2 different Cell Populations in Parathyroid glands?
Chief cells (PTH) Oxyphils - rare
Describe Pancrease?
Lies with abdominopelvic cavity, slender pale organ with nodular (lumpy) consistency
What are the 2 types of Pancreas cells?
Exocrine - pancreatic acini in clusters
Endocrine - Islets of Langerhands, - small groups cells scattered
Describe the Pancreatic Islets?
Extensive capillary netowrk - hormones ot blood
What are the 4 cell types in Islet?
Alpha cells - glucagen ( increase BG, Glycogen breakdon)
Beta cells - insulin ( low bg, increase glycogen synthesis)
Delta cells - inhibiting peptide ( inhibits release of glucagon and insulin, slow food absorption)
F cells - pancreatic polypeptide - inhibits gall bladder contractions
What are the 2 distinct endocrine systems in the Adrenal Gland?
Adrenal cortex (outer) - secretes steroid hormones - cholesterol Adrenal Medulla (inner) - neuroendocrine component
What are the 3 distinct zones of the Adrenal Cortex?
Outer - zona glomerulus - small (aldosterone)
Middle - zona fasciculata - biggest yellow (cortisol)
Inner - zona reticularis - brown (androgens)
Describe Adrenal Medulla?
Derived from neural crest and part of neuroendocrine system, brown, large pale cells and fine granular, cells are polyhedral in shape surrounded by rich network capillaries
Describe Hormonal Aging?
Cortisol increase with age
Sex hormones, melatonin and GH decline with age, HRT + youth and regeneration - price is cancer
